Donald Trump had earlier threatened to "spill the beans" about Cruz's wife, Heidi Cruz, after an anti-Trump super PAC released an ad showing an old nude photo of Trump's wife, Melania, implicitly questioning whether she would be an appropriate first lady. It was not made clear what Trump meant to imply with his threat.

While on the campaign trail for her husband in Wisconsin Wednesday, Heidi Cruz responded to Donald Trump's threats herself, saying she wasn't "worried" about the remarks.

"You probably know by now that most of the things Donald Trump says have no basis in reality," she told reporters.